In a process for manufacturing a semiconductor apparatus including semiconductor devices such as a transistor, a pattern miniaturization is an indispensable technique in order to increase the integration degree. Various lithography techniques have been developed in these years in order to further miniaturize the pattern. Such lithography techniques include an Extreme Ultra Violet (EUV) exposure technology that uses an EUV light as the exposure light.
The exposure light used in the EUV exposure technology has a very short wavelength of around 13.5 nm. Thus, the EUV exposure technology is recognized as a lithography technique that resolves a very fine pattern of 50 nm or less.
A mask used in an EUV exposure technology apparatus applies an electrostatic chuck system as the absorption system because the mask is used under vacuum. However, a mask defocus possibly occurs due to a particle attached on the absorbing unit or the variation of the absorption force in the electrostatic chuck system. When a mask defocus occurs in the EUV exposure technology apparatus, a defocus occurs in the transfer pattern on the wafer and a distortion also occurs in the transfer pattern. A lithography technique using an ArF light in the past can measure the mask defocus. However, it is difficult in the EUV exposure technology apparatus to measure the amount of flection of the mask (mask defocus) and the amount of deformation (distortion) of the mask. Thus, there is a need to measure the amount of flection and the amount of deformation of the mask even in the EUV exposure technology apparatus.